HIP 70 and outlook Exchange connection lost

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On several laptops I have disable de windows firewall and installed Host Intrusion Prevention 7.0. When The firewall option is enabled, Outlook 2007 is constantly loosing connection with Exchange 2003. This happens on some laptops, not all. When I disable the firewall option, Outlook works fine. What I also notice, are services that constantly stop and start. These stopping and starting services look random.
What option in the firewall settings have I overlooked, to have this random behaviour.